LTE and LTE-advanced are standards for wireless communication of high-speed data for user equipment (UE) such as mobile telephones. In LTE-advanced and various wireless systems, carrier aggregation is a technology where multiple carrier signals operating on different frequencies may be used to carry communications for a single UE, thus increasing the bandwidth available to a single device. In some embodiments, carrier aggregation may be used where one or more component carriers operate on unlicensed frequencies.